CARACAS - President Hugo Chavez says he was heading through downtown Caracas when he was shocked by the sight of a huge, nearly finished shopping mall amid the high-rise offices and apartments.

"They had already built a monster there," Chavez said. "I passed by there just recently and said, 'What is this? My God!' "

So the often-impulsive president told an allied mayor to halt construction and said this prime block of urban real estate should be expropriated. He said the sprawling six-story building might be put to better use as a hospital or university.

The exercise in drive-by socialism illustrates Chavez's tendency to govern from his gut, and to leap in when he thinks other government agencies - in this case city planners - aren't doing their job.

The new Sambil mall was scheduled to open in the La Candelaria district early next year, packed with 273 shops, movie theaters, and offices. Chavez complained - with reason, some experts say - that it would add yet more traffic to an area that's already too crowded.

"Stop it, Mr. Mayor. And we're going to review all of it. And we're going to expropriate that and turn it into a hospital - I don't know - a school, a university," Ch??vez said during his weekly broadcast on Sunday.

The newly elected mayor of the district, Chavez ally Jorge Rodriguez, told the president he would get the job done, though how remains unclear. Neither he nor Chavez spelled out possible compensation.

"There's a lot of concern because all of this was knocked down from one day to the next," said Victor Maldonado, who leads the Caracas Chamber of Commerce, Industry and Services. He told reporters the sudden decision to freeze one of Caracas's biggest investments is an arbitrary move that threatens 3,000 jobs and has led to a "rise in uncertainty" among businesspeople.

Constructora Sambil, the company building the mall, was closed for the holidays, and phones at its offices went unanswered.

Chavez, who has nationalized Venezuela's largest phone company, electric utilities and oil projects, suggested the property was too valuable to be left to commerce.

"How are we going to create socialism turning over vital public spaces to Sambil?" he asked.

Rodriguez, the district mayor, said Monday that downtown communities would be consulted on the "most appropriate use" for the building. "We're going to respect private property," he said.

Despite Chavez's calls for moving toward socialism, many Venezuelans have tended to ignore his exhortations to shed their consumerist habits. Shopping malls with stores such as Louis Vuitton and Timberland have sprouted up rapidly in recent years as windfall oil earnings have boosted the economy.

Yet, this particular mall a short drive down Urdaneta Avenue from the presidential palace seemed to especially irk Chavez.

Venezuelan architect Gaspar Arancibia said he agrees the mall was ill conceived, without adequate streets to handle the traffic - a symptom of perpetually poor planning.

"I agree with the president, but it was very late. It should have been stopped a long time ago," Arancibia said.

Now that the mall is nearly built, converting it into a hospital, school or university "will mean an enormous cost," Arancibia said.

Steve Ellner, a political science professor at Venezuela's University of the East, said Chavez sometimes tries to impose decisions when he thinks local institutions aren't performing as they should.

"Chavez, I think, is correct to a certain extent in criticizing this 'monster.' But that's not the way to do things," Ellner said. "Institutions are necessary, and I think that if this revolution is going to be successful in the long run, they have to establish new institutions in order to avoid this kind of decision-making process."